When Sally O'Neill's doctor told her she had an early form of cancer in one of her breasts, she didn't agonize about what she wanted to.
The 42-year-old mother of two young girls wanted a double mastectomy.
"I decided at that moment that I wanted them both taken off," says O'Neill, who lives in a suburb of Boston. "There wasn't a real lot of thought process to it. I always thought, 'If this happens to me, this is what I'm going to do.' Because I'm not taking any chances. I want the best possible outcome. I don't want to do a wait-and-see."
Sometimes a drug hits cancer hard. Sometimes the cancer cells are unfazed. But it's often hard to know which outcome to expect.
A group of scientists at the National Cancer Institute has spent the last three years turning some mathematical algorithms loose on giant sets of data to better understand the relationship between cancerous cells and cancer drugs.